


Chaleur

by armins_booty



Category: Shingeki no Kyojin | Attack on Titan
Genre: Alpha/Beta/Omega Dynamics, Alternate Universe - Modern Setting, Anal Sex, Dirty Talk, F/F, Laboratories, Lap Sex, M/M, Multi, Multiple Orgasms, Multiple Partners, Rimming, Wall Sex, omega armin
Language: English
Status: In-Progress
Published: 2015-02-11
Updated: 2015-04-26
Packaged: 2018-03-11 16:30:35
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 4
Words: 13,807
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/3331481
Author URL: https://archiveofourown.org/users/armins_booty/pseuds/armins_booty
Summary: <blockquote class="userstuff">
              <p>Armin Arlert has the perfect life. He lives in a beautiful home with two beautiful dogs and works his dream job as a scientist with amazing friends. Though he doesn't have a mate yet, he doesn't need to worry about that. People have been bothering Armin to volunteer as a test subject for the Alpha, Beta, Omega (or ABO) studies. Armin has always declined, but what happens when he accepts...?</p>
            </blockquote>





	1. Chapter 1

**Author's Note:**

> ay B^) new story by ME hopefully this one will be better than the others lmao. I've always wanted to do a story like this, mostly because i just want to explain how I see this shit working. tbh I'll probably find a way to worm some details in the story but if anyone wants me to just say what the fuck is going on inside their bodiies i will GLADLY.  
> A little side note: In this universe, omegas can only mate with omegas, betas can only mate with betas, and alphas can only mate with alphas. 'Bonding' hasn't been discovered yet.

**Notes for the Chapter:**

> ay B^) new story by ME hopefully this one will be better than the others lmao. I've always wanted to do a story like this, mostly because i just want to explain how I see this shit working. tbh I'll probably find a way to worm some details in the story but if anyone wants me to just say what the fuck is going on inside their bodiies i will GLADLY.  
> A little side note: In this universe, omegas can only mate with omegas, betas can only mate with betas, and alphas can only mate with alphas. 'Bonding' hasn't been discovered yet.

There were hands all over him. Caressing his body with feather-light touches; pinching, pulling, twisting, jerking, all over his body. Wherever the bodiless hands touched him, a wildfire of sensations burst out throughout his body. Everything was so hot. He was wet. There was moisture everywhere, making his hair stick to his face. He could feel the slick wetting his quivering hole, precum leaking from the head of his rigid cock. The hands touched him everywhere except where he wanted it- _needed it_ \- most. Guttural sounds escaped his tender throat, matching the barks that came from the mysterious hands.

_Barks?_

That wasn’t right. The scene faded, Armin being expelled from his wonderfully pleasant dream and pulled through murky water back into reality. He was in his room, natural light from the rising sun breaking through pale curtains that weren’t fully closed covered the bedroom in a beautiful golden light. In his sleep, Armin had somehow kicked away all of his blankets. His boxers, the only article he wore whilst sleeping, were tented and sopping wet with sticky fluids. A groan escaped Armin’s cracked, partly parted lips. The barking, coming from the foot of the bed, only continued. Slowly, Armin raised his torso to see just what had woken him from his slumber. Sitting on the mattress near his feet was a monochrome English springer spaniel, the large hound staring at Armin with an interested expression. No, the constant yapping wasn’t coming from that one. It was coming from the much smaller Cavalier King Charles spaniel on the carpeted floor below, the tiny pup having been too small to jump upon the bed. Armin cringed visibly. Why couldn’t they just let him sleep?

“I’m up, I’m up!” Armin grumbled and sat up fully. As soon as the trifling Blenheim dog saw him, she hopped over to him and pawed happily at the bed. “Can I take care of my straining hard-on, first?” Armin said with a teasing tone. Honestly, it was sticky and gross and he had to change. He hopped off of the bed, on the opposite side of his female pup, and onto the plush white carpet below. He waddled over to his closet, the feeling between his legs truly grossing him out. His pets followed behind him, yapping for food.

“Suki,” The excited Cavalier king Charles. “Jasper!” The quieter, but nonetheless happy, springer spaniel. “Calm down, jeez! You can wait a little longer for breakfast.” Armin grabbed a fresh pair of underwear and rushed to the conjoined bathroom, striding over the canines that were bounding at his feet. As soon as he had entered the crystal clean bathroom, he made sure to close the door behind him so the dogs wouldn’t follow him in. Gods knew what they would get into. Thankfully, his penis had grown flaccid, so he didn’t need to worry about relieving himself with pooches clawing at his door. He pulled off sticky underwear, tossing them into a hamper, and wiped himself clean with a damp washcloth. Once he was sanitary, he pulled on fresh undergarments. Armin had just finished his heat, as he was an omega, so this sort of thing was rather unusual. Armin tried to figure out why he was having such a lucid, lustful dream even after his heat, but nothing came to his mind. Maybe he was lonely? Armin scoffed at that. _I beg to differ!_ While he was still in the washroom, he washed his face and brushed his teeth.

When he left the bathroom, both pups were curled up right outside the door. “Come on, let’s go eat.” Armin started through his small cottage, walking from his bedroom into the main living room. From there, he entered the conjoined kitchen. First, he fed the dogs their usual kibble, then began on his own nutrients. Bacon, eggs, and toast. A typical breakfast. As he was scrambling said eggs, he peered out of the window above the sink. It was a beautiful morning, as always, out in the wilderness. As soon as he had graduated from university, Armin had moved onto the acreage he inherited from his parents. Already there had been a small cottage from their stays when Armin was younger. All it needed was a little cleaning and modernization and it was perfect to live in. It was an hour’s drive to the nearest city, and half an hour to his work place. All in all, it was perfect. Though it was very solitary, Armin had his puppies and his friends at work.

He finished his breakfast and dumped his serving onto a plate. He sat down at the kitchen table. It was a small kitchen table, and there were two seats parallel to each other. Armin always chose the one closest to the kitchen. He ate breakfast in silence, staring out the window to the slowly brightening world around him. If everyone in the world except for him had died in that very moment, Armin wouldn’t mind it at all.

Once his own breakfast was gobbled up, he let the dogs out into the vast expanse of wilderness. He could trust the dogs to not run away. They never had before, though they had gotten lost numerous times as little puppies. Armin’s legal land was bordered by a wired fence, letting the dogs know if they had strayed too far. Plus, Armin had bought tracking collars for them after the umpteenth time they got lost as babies.

Now that Armin had the cabin to himself he would be able to successfully dress himself for work. He stalked back to his bedroom, and as he walked by his desk his snatched his phone off the wooden surface to check the time and to see if he got any messages. It was almost 7! Armin was going to be late! Hurriedly, Armin pulled on the first articles he grabbed from his closet. Jeans and a shirt with a cat that said ‘très bien’ in swirly letters. As he left his room, he made sure to grab his laptop and close the door tight behind him. He put his laptop and phone into his bag, pushing around discarded folders and papers. He galloped to the back door, swinging it open wide and calling out for his two beloved babies. He only had to wait a moment before he saw them barreling down the field, racing each other to see who could get to Armin first. Armin had to move out of the way as they ran into the house, lest he wanted to get ran over by his own dogs.

“Okay, guys. You know the drill.” He spoke out loud to his pups. He knew that they couldn’t respond- Hell, he didn’t know if they understood- but he still did it anyways. “Historia will come at lunch to check in on you guys and to feed you! Be nice to her.” Historia was the kind little omega who lived yards away from Armin in her own quaint farm with her close friend, Ymir. They spoke frequently, and Armin was proud to call the sweetheart a close friend of his. Every weekday, Historia was kind enough to feed Armin’s dogs’ lunch whilst he was out at work. She also brought him extras from her farm, like eggs, vegetables, and fresh meats. It was always a nice treat. The dogs adored her, too.

With a few parting belly rubs and smooches, Armin was off. He owned a beaten up truck that was caving in on itself but, hey, it got good mileage and it had seat warmers and a working radio, which was all Armin needed in a vehicle. He gently tossed his bag into the passenger seat and started off on the half hour trip to the research labs. He had bought a cable to connect his phone to the radio, for he didn’t get radio reception this far away from the city. He liked listening to his own music, anyways. He had a rather different taste of music. It was like a melting pot- everything from pop to rap to rock to k-pop all mixed together to create Armin’s unique style. But, his all time favourite had to be Taylor Swift. He pulled away from his acreage, the beat to ‘Asylum’ by Disturbed bidding him off.

The ride wasn’t all that unpleasant, though it would’ve went much better if Armin had the time to prepare his coffee for the road. Things didn’t always go in his favour, and Armin respected that. Pulling into the parking lot, Armin was dancing to his best ability to ‘Shake it off’. He was also singing rather crudely along to the music as well. He pulled out his keys and the engine died with one last sputter. He grabbed his bag and his phone and used his foot to help open the door for him, all while singing to the imaginary music in his head.

“-Haters gonna hate, hate, hate, hate, hate. Baby I’m just gonna shake, shake, shake, shake- Shake it off, shake it o-“

“Hey, Arm.”

Armin yelped loudly at the sudden chuckle that came from behind him. He dropped his phone, thankful that he had a protective case for it as he bounced on the concrete. Armin, after picking up his phone, turned on his heel to glare daggers at the culprit. It was none other than Jean Kirschtein, his cocky smirk making Armin all the more distressed. Ah, but Jean looked so hot today. He had gotten a haircut, Armin noticed. The sides of his head had been freshly shaven. Damn it, it should be illegal to look that fine!

“Jean, you ass, I dropped my phone!” Armin scolded, as if it were all Jean’s fault for the whole thing.

“Wha- why is that my fault!?” Jean laughed, finding Armin’s behaviour to be rather adorable. He leaned forward, holding his body up with the arm that was propped up against the dirty old truck, right beside Armin’s head. “Are you from Tennessee, ‘cuz you’re the only ten I see.”

Armin snorted. “Jean, that’s like the oldest trick in the book! And you know that I’m from Montreal.”

“Oh, that’s right!” Jean perked up suddenly. “Talk French to me babe.”

“Vous êtes un âne.” Armin moved from Jean’s grasp, going towards the beautiful building that stood before them.

“My shorts are moist.” Jean purred, following after the shorter blond.

Armin ignored him. The research building was three stories, plus a basement. It, just like Armin’s home, was in the middle of a woodland. Beautiful, probably exotic and maybe illegal, flowers sprouted all over the place. It was finely trimmed, thanks to the horticulturist Marco. The building looked somehow so welcoming, with bright, yet gentle, colours to decorate the décor. Scientific buildings were usually so intimidating, leaving Armin glad that he worked at the most friendly of the bunch. Each of the stories, excluding the basement, had a different major. The top floor worked with modern medicines, the second for biology, and the ground floor was specifically for the mysteries of Alpha, Beta, and Omega dynamics. Armin worked for biology. He adored everything about it. Jean, the big dork, worked in Alpha, Beta, and Omega studies. Out of the three, the ABO studies had the most attention and needed most volunteers from the public populace. Most volunteers lived in the research building.

The pair entered the building, Armin greeting the secretary at the front desk before he went straight for the elevator. He knew what was coming. For weeks, it had been the same thing.

“Hey, Armin,” Jean called. Of course, he couldn’t avoid it today. “We still need more omegas, since they are such a rarity.”

“I don’t want to be studied, Jean.” Armin called as he retreated into the elevator.

“But Eren talks to you abo-” The door closed, leaving Armin to sweet peace.

Armin didn’t feel any prejudice towards the ABO studies, nor the volunteers. He just didn’t feel like being poked and prodded at for a living. Though Eren, an infamous Alpha volunteer, always told Armin that it was like being legendary. Free food, free living space, and everyone was so nice even though he was such a prick to them.

Armin shook his head, clearing his fogged mind. He had work to do today! He wouldn’t be distracted, especially by simple thoughts like this. The elevator brought him up to the third floor in less than thirty seconds, and he was off.

Work that day, as per usual, wasn’t that exciting. Fun, yes. It was always fun. Armin would never work somewhere he didn’t enjoy it. It just wasn’t stirring. His morning was filled with paperwork, and then it was lunch in the cafeteria. Jean, as always, sat with Armin, chattering away absently. After lunch Armin got to go into the labs. Today he decided to work with environmental chemistry. He was observing the innards of a frog that had died from a type of flesh-eating disease. He had to see if it would spread to other animals or, most importantly, humans. When sickly coloured blood squirted onto his face, Armin blindly rushed to the nearest bathroom. Instantaneously, he smacked right into a broad chest.

“Woah, Armeme, slow down.” Rough arms gripped his own, steadying him before his fell.

“Ah,” Armin knew instantly that it was none other than Eren Jeager. Who else used those dumb nicknames for him? “Sorry. I got some blood on my face that could possibly have flesh-eating bacteria harmful to humans. Could I please wash my face before I die?”

“You’re not gonna die.” Eren scoffed, though he began to lead Armin off to the bathroom. “I’ll kill all the bacteria before it can get a chance to hurt you.”

Armin chuckled lightly to himself. “That’s not how these things work, Eren…”

Eren didn’t listen, instead only dragging Armin to the bathroom. Armin blindly stumbled behind him, not having much other choice. Eren sat Armin down on the counter and grabbed a paper towel, putting it under the stream of cold water from the automatic faucet. When the paper towel was moist, he dabbed away the smear of blood on Armin’s cheek.

“Does it look agitated?” Armin asked as Eren was readying a second paper towel, this time dumping loads of hand soap onto it.

“Nah. Looks fine. Maybe it isn’t harmful to humans.” The tan man spoke.

“Or we got it in time.”

“Arm-man, you gotta look on the bright side sometimes!” Eren prodded Armin’s sides, making the smaller of the two squirm.

“I’m a scientist. I look on the logical side.”

Eren pouted and reeled back to let Armin off the cold, and wet, counter. “Lame scientist nerd.” He teased as he walked from the bathroom, Armin following suit. Before they separated in front of Armin’s lab, Eren brought the attention upon himself once more.

“Become a volunteer.”

“Eren, we’ve went over this numerous times. I don’t want to be a science experiment.” Armin crossed his arms and arched a thick brow, giving Eren something the other scientists dubbed as ‘The Stare’. The stare that could make the strongest of men quiver and give in.

“But we’re doing really cool things!” Eren insisted, grabbing Armin’s small hands to hold them in his own calloused ones. “We’re seeing how omega blood and saliva reacts to alpha and beta blood and saliva. But we’re short on omegas… And you’re the only omega in the whole building! And we know you. Like the back of our hands!” Eren hopped in spot a bit. “It’s really not all that bad. And I’m sure they’ll let you keep working!”

“First… Why would they need to know how omegas react with alphas and betas? Every dynamic can only mate with its own dynamic.” Armin said with a suspicious stare.

“Everyone knows that, blondie. But they’re scientists. And scientists need to know the answer to everything!” Eren overdramatically waved his hands around.

Armin sighed, but smiled warmly at the giant dork before him. “Second, I’ll see… I guess.”

Eren whooped loudly, fist pumping. “Fuck yeah! I’m gonna go tell Jean the Cherry Bomb!”

“I said I’ll see!” Armin called after the man-boy, watching him scamper away, probably back to the ABO labs. Why he was even on the third floor, Armin had no clue.

The rest of the day went on without any interruptions. Armin still hadn’t figured out the truth of the frog, but he knew that he had to get home to his puppies before they got too hungry or broke something. He packed up his things, putting them all into his bag before walking out of his lab. The sun was starting to set, making the whole place look enchanting from the outside. Armin knew that by the time he got home the sun would’ve set already, so he had to watch out for wild animals. Armin couldn’t see Jean’s car, so the other had already left. Armin boarded his own truck and started off home.

His predictions were right, as by the time Armin got home the sun had already set, leaving everything dark and spooky. He could hear crickets buzzing all throughout the tall grass, and in the far distance he hear a wolf crying into the night. He entered his cottage, turned on the lights, and was instantly attacked by two adorable dogs.

“Hello, babies! Did you miss me?” Armin laughed and gave them their well deserved cuddles. As well as their well deserved kibble, of course. As the two ate, Armin spoke of his day to them. He spoke of Jean, being the same butthead as always and pestering him about joining the ABO studies. He told them about all the paperwork he had to do, and then the frog incident. Then he spoke of Eren.

“He wants me to volunteer really badly… doesn’t he?” Suki padded over to Armin, her head swaying from side. She nuzzled up against the boy, her tail wagging erratically. “But, I mean… Why do they want to see how omegas react to other dynamics? And I don’t want to be a little test bunny… I want my body chemical free! And I want to be _free,_ too! But… augh! I don’t know! Should I do it…? I guess I’ll see how I feel tomorrow… Maybe. Ugh…”

So Armin went to bed, those indecisive thoughts still wearing on his mind throughout his rest.

And throughout the next morning, as well. Even as Armin bid his dog’s farewell and headed out to his truck, he still didn’t know what he wanted to do!  When he finally reached the lab, he was an anxious ball of unmade decisions. He was able to make it to the elevator without being bothered by Jean, though right before the doors eased shut someone called to him to hold it open. So, he did. A tall and muscular blond man pushed his way into the elevator, and Armin recognized him instantly. Erwin Smith, president of the ABO studies. What an ironic encounter. Or, maybe, it meant something else…

“Good morning, Mr. Arlert.” Erwin nodded a greeting to the much slighter man.

“Good morning.” Armin returned the greeting, standing silent until Erwin spoke again.

“Jean has been bothering you about our field of work, I assume?” Erwin inquired, glancing at Armin out of the corner of his eye.

“And Eren.” Armin said with a slight chuckle.

“I think you should take them up on the offer. I would, as well, very much like to have a trusted omega in our hands.” Erwin was trying to sound kind, but Armin just... something rubbed him the wrong way.

“That’s the thing,” He started, “I don’t _want_ to be in your hands. I would very much like to help with the discovering of many things but… I don’t want to poked and prodded at, like caged cattle. I want to still have my freedom.”

Erwin seemed oddly surprised at the answer he received. “Trust me when I say this, Mr. Arlert. As the president, I know that our volunteers are not poked or prodded at. Nor are they kept like cattle. We treat them with the upmost respect, knowing how frightening their situation can be. If you did aid us with our research, I can comfort you to say that you will have freedom. You can continue your job and go about the lab freely, though we might need you to be kept here overnight in some dire situations. There might be some examinations, but they would be just like going to the doctor for a check-up.”

Armin spared a glance up at the man, to be shocked to see him smiling fondly at Armin.

“If you decide to take up the offer, please do not hesitate to come visit me in my office at lunch. I’m eagerly waiting your response.” With those as his parting words, Erwin left the elevator.

Armin was shocked. But he was even more confused.

At least he had until lunch for his final decision.


	2. Chapter 2

**Notes for the Chapter:**

> EDIT: haha yea h.  
> im so angry. our internet connection is being really dumb and i can't go on the internet on my laptop so I can't post the next chapter. I s2g i'll post it as soon as the internet is working again. we're getting new internet so yeah. it could take from a week up to a month pls save me. goOD thing is my phone still works haha. hah. hhhng.

Working was not easy as his mind was in the gutter. He had accidentally destroyed two samples of the odd frog flesh-eating disease in the span of two hours. The head of the research facility told him that he needed to go take an early break or something. And so Armin happily complied, walking down to the lounge in the first floor of the building. The lounge was kind of like a small food court, build in a dome-like extension to the main building. Its walls and ceiling were made entirely of glass. Inside the lounge was a Tim Hortons, Subway, and a little convenience store. Armin sat in the lounge, staring out the large windows at the rustling leaves of late spring. A bird hopped to and fro on a branch, probably looking for grubs for its young. Armin smiled, a slight sigh escaping him. The bird must feel so proud, having its very own babies to care for. It would get to see all of their accomplishments, like their first time flying. Armin pinched himself. Why was he thinking like that? And why did his stomach feel tight? Why was he getting jealous over a fucking bird!?

Someone abruptly sitting next to him and calling out his name knocked him out of his idle thoughts. It was none other than Eren, probably coming to bother Armin about volunteering once more.

“Eren, I…” Armin stared at Eren. He looked so hopeful. Armin had known Eren since they were young, when they both lived in the city. They went to the same elementary, the same high school, and the same university. Eren was Armin’s best friend, and when Armin had decided to become a scientist, Eren wanted to become one, too. Of course, he wasn’t really currently a scientist and of course, he probably never would become one. But, it was good enough for Eren if he could just be there for Armin. A sudden thought hit Armin. Why did Eren want Armin to join the ABO studies so badly? Could it be that Eren was lonely? Armin did live half an hour away, and he worked on the top floor of the building. He hardly had time for Eren, who had abandoned his city life for Armin. Armin found himself smiling fondly at Eren. “I know what you’re going to ask me.” Armin said before Eren had time to speak. “So I’m going to say this- I’ll check it out, okay?”

Eren jumped from his seat, throwing his hands into the air and whooping loudly.

“But!” Armin interrupted Eren’s joyful dance. “That doesn’t mean I’ll join for sure.”

“Good enough for me!” Eren chortled, too overjoyed to see anything negatively. “We have to go tell Erwin! He’ll be overjoyed!”

Armin rolled his eyes, following Eren as he was led away. “I wouldn’t say overjoyed. Erwin is a mature adult, unlike you.”

The walk to the office was filled with Eren’s joyful jabbering, telling Armin all about the lab and how fun it would be, now that they were ‘working’ together. Eren abruptly kicked Erwin’s office door open, much to Armin’s dismay.

“O-Oh my god, Erwin, I’m so sorry! Eren is out of hand!” Armin gasped, trying his darn best to excuse the rude behaviour of his friend as he was pulled into the office. There was no escaping now.

“What is this all about?” Erwin asked, seemingly ticked off that he had to interrupt his meeting with an apathetic looking man sitting across from him. Said apathetic looking man turned around in the seat, glaring daggers at the two newcomers. Armin shied away, hiding behind his childhood friend.

“Armin said he would join the studies!” Eren hollered.

“N-No, I didn’t say…” Armin tried, but he was easily interjected.

“Yeah, great, could you fucking leave now, you brat? Didn’t I say I don’t want to see you fucking around anymore?”

Armin was appalled by the behaviour of the dark haired man. It apparently showed in his face, seeming how Erwin chuckled.

“Shut up, Levi!” Eren snapped.

Holy shit, Armin thought to himself. Did Eren want to be beheaded!? Eren was returning the blinding glare of the other man, whom Armin thought could only be someone of importance, seeing how comfortable he appeared in Erwin’s office.

“E-Eren! Respect-”

Of course, Armin was ignored as Eren and Levi went off into their own world, sneering and barking harsh comments at one another. It was a battle of testosterone!

“Armin,” Erwin’s strong voice pulled Armin out of his concern for his friend. “Is what Eren said true? You’re going to join the ABO studies?”

Armin shifted awkwardly under Erwin’s gaze. “I- um… I said I would check it out… I want to see what it’s like.” He worried his bottom lip between his teeth. He hoped that was the correct answer.

“Good enough for me.” Erwin said. Didn’t Armin just hear that come out of someone else’s mouth? Erwin arose and walked around the desk to stand in front of Armin. The height difference was laughable.

 “So, shall I show you around?” Erwin asked the slight boy beside him. Armin eagerly nodded, and the two set off whilst ignoring the other battling men. _They’ll be fine_ , Erwin tells Armin.

Erwin lead Armin throughout the laboratories, welcoming him into each test site to look around. Erwin was right when he said that the labs were made to feel comfortable and look like any other doctors lounge. It heavily contrasted to the conditions in which Armin worked. They had to interrupt one or two tests, but neither Erwin nor the scientists seemed to mind. Plus, Armin got a better picture of what went on behind the scenes. One lady, though, seemed almost too happy to see Armin entering her office.

“Armin Arlert!” She exclaimed, rising from her desk and just giving up whatever she was typing at her desktop. “I’ve heard many wonderful things about you!”

The rambunctious woman approached Armin and pulled him forth by his shoulders. Her boney hands ran through his hair, pulled at his skin, forced open his mouth, and then went to lift up his shirt. Armin forced her to stop things there, awkwardly moving backwards to be side by side with Erwin.

“This is Hanji,” Erwin explained, “One of our lead scientists. She’s very… different in her ways. But she gets things done. Almost too well, if I do say so myself.”

Hanji smiled from ear-to-ear. “I’ll take that as a compliment? Is our lovely little Arlert going to be joining our facilities?”

“I sure do hope.” Erwin said. “I’m showing him around the labs.”

“Ah, yes! The labs are very nice, aren’t they, Armin? When I first came here, I expected something totally different! Like out of those stories you hear of animal testing. I honestly thought I was in the wrong place, but I was gladly wrong.”

Though she had a different, more out there disposition, Armin thought that Hanji seemed like a very sincere and smart person. He instantly enjoyed her company. Erwin brought Armin from the room and over to the elevators. Armin was ushered inside, and his senior pressed a button on the keypad.

“I’ll show you to the rooms. They are in the cellar of the building.”

Armin raised a thick brow. “You know, saying cellar makes me think of a cultic torture chamber. Just say basement. Or lower ground floor.”

Erwin scoffed, and when he spoke his voice was laced with amusement. “I-I’m sorry?”

Armin laughed as well. Soon enough, the doors to the elevator opened once more and the duo was allowed out. Armin wasn’t expecting the basement to look like a story of an apartment complex. He wasn’t expecting anything of this tour to be as it was. The two began to walk down the hall.

“As you can see, the ABO subject rooms look just like any other rooming complex. Each subject gets their own room, which they can decorate to their liking. There is a community recreational room, and all meals are acquired for. We prefer for our subjects to not leave the property.” Erwin spoke diligently, as if he were a landowner trying to sell to Armin. They reached the end of the hallway, to a set of double doors that could only lead to the rec. room. The little amount of rooms surprised Armin.

Erwin turned to face Armin, his demeanour taking a sudden serious turn. “So, Mr. Arlert. Have you made your decision? Will you be working with us to solve the mysteries of Omegas?”

Armin looked away from the intimidating Alpha before him. He… He was unsure. “If I do, will I still be allowed to work?”

“Yes.” The response was quick.

“Will I be able to bring my dogs with me?”

“If they are behaved well enough, then yes.”

“Will I be able to leave whenever I want to?”

It seemed that question staggered Erwin, but he responded. “Yes.”

“Then… I guess there’s no harm in trying it out?” Armin said with a crooked smile and awkward shrug.

“Great! Then you will be-”

“Yes, Armin, I fucking knew you would do it!” A loud call from behind them knocked the conversing men out of their exchange. Armin turned, and Erwin did not seem amused; not in the slightest.

“Eren…” Armin sighed heavily, not having the time to react as he was vehemently pulled into a clogging hug. “Yes, yes, okay! You’re acting like a giant baby. Pull yourself together.”

“I’m not a baby!” Eren argued, pulling back with a stern expression. He had a black eye, undoubtedly from his scuffle with Levi. Armin simpered.

“Fun’s over. Armin, go speak to Jean and he will commence the project. Eren… go do something that won’t bother anyone who is working.” Erwin had to use force to wrench Eren from Armin. He gave Eren a great push forward, whilst he held onto Armin’s shoulder. “If you need to speak with me or have any questions,” Erwin whispered, “Do not be afraid to visit me in my office.” Armin nodded, straightening his back with the oddest feeling of pride. “Now, I trust you know where to find Jean. I have some things to take care of with an unruly Beta.”

Armin bowed and set off, walking past Eren who was walking back into the room he came from, presumably his own. Once he was back on the first floor, it was guileless to find Jeans office. The blond boy walked inside, as if he owned the place, and sat atop the desk on which Jean was working on his laptop.

“Armin? What are you doing in here?” Jean queried. “Shouldn’t you be working?”

“Well,” Armin started with a slight grin. “I guess I am technically working, now that I’m ABO volunteer.”

“Holy shit, Arm!” Jean exclaimed as he stood up, dragging Armin into his second embrace in less than half an hour. A laugh bubbled from the small boy, and he returned said hug. “That’s great! Wow, oh my god, what convinced you?”

Armin hummed. “Uh… I dunno. I guess I was thinking about things, and Erwin gave me a tour. It’s not a bad place, and the people are nice too.” Armin could see how proud Jean seemed. “Oh, and he told me to come to you to start my volunteering stuff.”

“Yes, of course, take a seat.” Jean motioned to the plush chair opposite of his own. Armin did, and the taller man followed suit. “I guess we can start with the basics, and just tell me what you know about ABO’s.”

Armin arched a brow, and Jean answered the question that was dancing on his lips. “Yes, we do this for everyone. Just to see if they are too stupid for the tasks.”

With a shrug, Armin began. “Okay, just saying, but you do know that I _am_ a scientist, right?” Jean glared at him, so Armin continued with a laugh. “Well… Uh, I guess… Decades ago, there was a mutation that was founded in humans, yeah? Their senses were better, and made them pretty much better versions of humans- they were faster, stronger, smarter. The mutants started to breed amongst each other, which only created more of them. Once there were more, it was easier to see that, within the mutants, there were three different _types_. The first type was the strongest of them all. Natural born leaders, their strength matched entire human armies. Other mutants were drawn to them, naturally wanting to obey. They were named Alphas, much like in the wolf hierarchy. The second appeared to be most like the humans. They were still quite amazing and put humans to shame, but there wasn’t that much special about them. They were the best at talking out of the three breeds, which is why they were usually the second in command to the Alphas. They became the Betas. The last were definitely the weakest. Even to humans, some of these mutants appeared weak. But, that is what made them strong- kind of. Not really. These mutants were called Omegas, for they were the weakest and most submissive out of the bunch. They were bullied by the other mutants, which is why they are the rarest of the breeds. Omegas can read the atmosphere quite easily, unlike the bloke Alphas. It is said that an Omegas scent can calm the wildest Alpha.” Armin blushed and rubbed the back of his neck. He didn’t understand why he got so embarrassed talking about Omegas. Probably because he himself was one. “During certain times of the month, all three breeds suddenly had an abrupt switch in their hormone balance. Their hormones went crazy, and the desire to, um… _breed_ became too strong to handle. Those were later named heats. Why everything is based off of canines, I don’t know. Eventually, ABO mutations began to take over the normal, nicknamed Provectus, humans. In the end, Provectus humans died off and the ABO humans remained.”

“Is that all you know?” Jean asked with a quirked brow.

“God no.” Armin scoffed and continued. “I know that these mutations had something to do with chromosome imbalance. In later years, once the sciences were more advanced, it was discovered that a third chromosome was discovered in the ABO’s. Along with XX, or XY, chromosome X, Y, or Z was added into the mix. An Alpha male would have XYX, and an Alpha female would have XXX. A beta male would be XYY and a Beta female would be XXY. The strangest chromosome imbalance occurred in the Omegas, where a totally new chromosome was founded- Z. An Omega male would have XYZ and an Omega female would be XXZ. Um, I think the purpose of the Z chromosome is still unknown…” Armin shrugged for the umpteenth time. “I know pretty basic stuff…”

“You don’t know why a dynamic is only limited to breed with its own dynamic?” Jean asked, and unbeknownst to both parties, had leaned forward quite a bit during Armin’s rundown.

Armin slowly shook his head, staring at Jean with a confused expression. “No… Why would I need to know that?”

Jean waved a hand in front of his face. “No, it’s nothing. Is that all you know?”

“Hmm… well, putting the sciences aside, I know that, before they apparently became extinct, Provectus humans vandalized all known records of ABO studies, forcing them to start over with only word of tongue as a source of information. I think, starting around that time, is when the whole dynamics breed with their own dynamics thing started, yeah?” Armin tilted his head curiously, like a dog awaiting praise. Along with science, Armin was also a history nut.

“Yes, that’s correct. Well, Armin, you know more than enough.” Jean smiled and arose from the chair. “Which is obvious. For now, I must speak to Hanji about certain things, like where we will begin with you. I would suggest you go make friends with the other volunteers.” Jean walked Armin to the door, bidding him a kind farewell, before they went their separate ways.

That was easy, Armin thought to himself. He was expecting a mind rattling, emotionally scarring test for his first experiment. He was glad that he guessed wrong. But why did Jean need Armin to tell him all the information he knew? That bit about them asking all the volunteers about that was bullshit, Armin could easily tell that. As he stepped into the elevator, Armin shook the nasty thoughts from his mind. It was time for him to meet the other volunteers, that weren’t Eren! Except, Eren always had to find a way to wriggle himself into any position.

“Armin, Armin!” Eren hollered, bursting from his room almost as soon as Armin walked past.

“What the shit, where you watching for me?!” Armin accused, clutching his throbbing chest.

“Maybe I was. But come on, now that horse-face is done with you, you have to meet the others!” Eren grabbed Armin’s hand and intertwined their fingers. Armin thought that Eren seemed a little too excited over this whole thing.

Bursting into the recreational room, Eren hollered, “Guess who’s here?”

“Fucking shit.”

“Could you shut the fuck up?”

“Hey, Eren!”

All the responses were different, but all were to be expected when dealing with Eren. Armin took a glance around the room. It looked like a peaceful place. There were some couches facing each other with a coffee table between them in the center of the room, and a quietly buzzing television sat in one corner of the room with its very own couch in front of it. There was a pool table, a bookshelf filled to the brim with books, a counter with a blender, sink, and coffee machine, and a jukebox. A fucking jukebox. Armin covered his grinning mouth with one of his hands.

Sitting in the center of the room on the couches were four bodies playing a game of cards. A blond beefcake sat next to a much smaller skinhead, and opposite of them sat a cheerful looking brunette and a dark-haired Asian woman. Sitting in the loveseat before the television was a blonde lady with a very prominent nose reading a book.

“It’s Armin. I told you he would come!” Eren thrust his arms out in front of Armin, like he was Vanna from the Wheel of Fortune.

“No shit! I didn’t believe you.” The small man with the buzz cut, even smaller than Armin, stood up and abandoned the game to approach the newcomer. “Hey, Armin! We’ve heard a lot about you from Romeo over here.” Eren’s face turned bright red. “I’m Connie. Over there is Reiner, Sasha, and Mikasa. Little Miss Social all the way over there is Annie!”

Armin smiled softly. “I would introduce myself, but I see you already know my name.”

“Eren talks about you nonstop!” Reiner guffawed from the couch. He reminded Armin of the jovial team captain from teenage sports movies.

“I do not.” Eren sneered, stalking over to the couch to steal Connie’s spot and punch Reiner right in the arm.

“You really do.” The stoic Asian, Mikasa, butt in. She intimidated Armin, and Armin didn’t even know her.

“Anyways, let’s talk about something else!” Eren quickly suggested. He didn’t seem to mind as Connie waltzed over and threw himself on top of him.

“Are you going to sit with us, Armin?” Mikasa asked, lowering the bright red scarf to offer Armin a gentle smile. Armin took back his previous comment. He drew near the couches, having no time to complain before Sasha pulled him down next to her.

“So!” She exclaimed loudly. “Armin is an Omega?”

Armin nodded.

“Bertholt will be so happy!” Connie said. “He’s been the only Omega here for a long time.”

Eren spoke, “Speaking of which, where is Bertholt? In his room?” A nod from Reiner answered his question.

“What is everyone’s dynamics, then?” Armin asked, wanting to get to know these people.

“As you know,” Sasha said. She sure liked to talk, but Armin didn’t mind. “Eren is an Alpha. So is Reiner and Mikasa! Connie, Annie and I are Betas. Bertholt, who isn’t here, is an Omega too. Isn’t that great? You’re not alone!”

Armin shrugged. “I… I guess?”

“Hey! Armin doesn’t have a room yet! Can he share with me?” Eren jumped up from the couch, successfully pushing Connie off of his lap and onto the floor. A loud ‘oomph!’ came from the floored Beta.

“No way.” Mikasa said, voice as steady as ever.

“Yeah, you’d try to jump him on the first night!” Sasha laughed, pointing an accusing finger at Eren.

Eren seemed flabbergasted, but the bright blush dusting his cheeks proved them right. “W-Wha- I would not!”

“That’s illegal.” Connie put his two cents in, still laying on the floor.

Armin watched his new peers argue amongst themselves, a caring smile making his cheeks ache. He had forgotten how long it had been since the last time he was together with a bunch of people like this, but it was surely a welcomed change. He hoped he would enjoy the time spent with his new friends.

**Notes for the Chapter:**

> i know nothing about chemicals and chromosomes i'm just making shit up for the plot okay??


	3. Chapter 3

**Notes for the Chapter:**

> i have no idea how to do anything sciencey. all hanji is doing and talking about with armin is t o t a l b u l l s h i t.  
> btw, for the blood mentioned when armin goes into his heat, it's kind of like a period?? if that makes sense. a really small, singular wave of a period

“Okay, Armin.”

Armin opened his eyes slowly, the bright light of Hanji’s laboratory being a shock to his previously closed eyes. He was sitting in a hard cushioned chair that reminded him of a dentist’s chair, and his arm was outstretched beside him.

“The hormones should take action in a day or two.” Hanji said as she threw out the needle in the biohazard waste bin and tossed her gloves into the trash. “Just sit back and relax for fifteen minutes, just in case you have a reaction.”

Armin shrugged awkwardly, his right arm feeling numb from the needle that was inserted into him. “So… What are these hormones, exactly?” He questioned.

“XYX blood.” Hanji hummed as she tapped away on her laptop.

Armin sat up. “Why did you put Alpha blood into me?”

“You are the nosiest volunteer we’ve ever had.” Hanji snickered, turning around in circles on the spinning chair. “We just want to check out the chemical reactions. We’ve done this to Bertholt, but you’re a scientist so you should know that we must do a test numerous times to confirm the results.”

A slight grumble came from the blond and he rubbed the Hello Kitty Band-Aid Hanji had kindly given to him. “Yeah, but I hate needles…”

Hanji laughed and flicked Armin in the arm. “Don’t be a baby. Babies are useless members of society that are only good for crying and pooping. They don’t even pay rent.”

“What do you have against babies?” Armin found himself laughing alongside the brunette.

“I was a baby once…” Hanji sighed heavily, looking out of the window overdramatically. She pressed her hand against the glass.

Armin’s fit of giggling was interrupted by a wave of dizziness. His head lolled about and he tried to press a hand to his forehead, but missed and only thunked his nose.

Hanji perked up. “What’s wrong?”

“I just feel kind of dizzy…” He said softly.

“Ah! Your mind is confused about the intruding chromosomes. If things go as they went with Bertholt, your white blood cells will start attacking the new blood and in a couple of days your body will be rid of the XYX blood!” Hanji appeared a bit too excited about simple chemical reactions in Armin’s blood.

He cocked an eyebrow, but reluctantly said, “Alrighty then. Can I go? I’m hungry.”

A nod came from Hanji and she helped Armin stand. She showed him to the door, and the blond was off. It had been a week and a half since Armin had fully became a volunteer. It was a peaceful thing, unlike he had expected. He was able to spend more time with Eren, and he was getting closer with the other volunteers. Especially Mikasa and Bertholt. Sadly, Armin wasn’t allowed to bring his dogs to the volunteer apartments. But, luckily for him, Christa was kind enough to say that she would care for them for Armin. Besides, he could still see them on weekends. It was still sad, though.

As Armin was walking back to his apartment, he bumped into Erwin and Levi.

“Mr. Arlert, just the man I was looking for.” Erwin said and stopped right in front of Armin, stopping the smaller male from advancing with his brick wall of a body.

“Hello, Mr. Smith.” Armin said back with a smirk. His smirk was gladly returned.

“I have a proposition. Though, I’m sure Hanji has already spoken to you about this.” Erwin started, clasping his hands behind his back. Levi was silent the whole time, his thin brows pulled into a glare.

Armin racked his brain, but couldn’t recall Hanji speaking to him about anything out of the norm. Before he could voice himself, Erwin continued.

“There is a certain test the lab wants to undergo, but there has been no suitable persons for that. We need an omega.” Armin was about to butt in, asking about Bertholt, but Erwin stopped him with a raised hand. “We _have_ asked Bertholt, if that is what you’re wondering. He had declined. Anyways, continuing where I left off, we need an omega. Besides Bertholt, you are the only omega we have. So if we were to initiate the test, we would need you.”

Armin was getting suspicious of this. It just rubbed him the wrong way. “Alright…” He said slowly, cautiously. “What is this ‘test’?”

Erwin cleared his throat. “You see…”

Levi rolled his eyes and stepped forward. “You need to get fucked.”                                            

Armin’s eyes bulged out of his head, and his jaw dropped. “I… W-What? I beg your pardon?”

“You heard me.” Levi grumbled, crossing his arms. He didn’t seem to have any dignity! “The test needs an Omega to get fucked by an Alpha and a Beta. You would get fucked by two Alpha’s and Beta’s, ‘cuz why not?”

Armin was sure he was blushing. He could feel his face burning with humiliation.

“Levi, you’re too brash.” Erwin scolded. “But, what he says is true, Armin.”

Armin was totally flabbergasted. What were these two saying?! Was this a prank?

“You would be in your heat, so that would also be a way of coping.” Erwin said, as if he were trying to make the situation sound better for the young Omega.

“And,” Levi butted in. “Seeing what experiment Hanji just did to you, your heat should be coming any day now.”

“I don’t understand!” Armin exclaimed. “My heat isn’t due for another two weeks, at the least.”

Levi shrugged nonchalantly. “Whatever. Just wait and see. We got important big boy shit to attend to, so you go do whatever Omega’s do. Probably jerk off.” Levi shouldered past the still gaping Armin.

“I’m sorry to be leaving so quickly, Armin. You have a few days to decide.” Erwin nodded at Armin and followed after Levi, leaving Armin to stand in the hallway.

The first movement Armin made was to cover his face with his hands. This couldn’t be happening…! He had so many questions. Wasn’t it illegal for an Omega to have sexual relations with Alpha’s and Beta’s? And what would the test even accomplish? And, with what Levi had said, what did Hanji really give him? This was too much for Armin. The little Omega ran down the hallway, nearly crashing into the stairway doors with how fast he was booking it. This was no time for elevators, he needed to rush down the stairs! The stairs were much quicker than the elevator, even with Armin nearly tripping several times.

When he finally reached the volunteer apartments floor, he ran past his own room and right into Eren’s.

“Woah, hey Arm.” Eren said, voice laced with surprise as he put down his Samsung. Gentle background music from an app could be heard. “What’s up?”

“In the span of you volunteering here, have you ever had to do sexual tests?” Armin asked.

Eren raised his brows in surprise. “I, uh? When I first got here they did a medical check-up and they checked how big my dick was.”

Armin breathed out through his nose. So, that meant that intimate experiments weren’t common here.

“9 inches, flaccid, for your information.”

“Eren what the fuck kind of monster do you have down there?” Armin deadpanned.

Eren grinned and shrugged, trying to seem as blasé as he could. “Alpha instincts, man.”

“That’s… not insti- Okay, buddy.” Armin giggled and hopped onto the couch, getting himself comfortable.

Eren sat next to him. “Why did’ja ask that, though?”

Armin rolled his head back and grinned at Eren. “I just wanted to know how big your dick is.”

Eren’s eyes widened hopefully. “Really?”

“No.” Armin laughed and punched Eren’s shoulder.

“Aw, I’m wounded.” Eren pouted and nuzzled his forehead into Armin’s own shoulder. “Nice Hello Kitty Band-Aid.”

“Thanks.” Armin hummed, all uncomfortable thoughts of testing gone from his mind. With Eren, he was in a good state of mind.

* * *

 

Levi was right.

Just two days after Armin’s encounter with Erwin and Levi, Armin plummeted right into his heat. When he awoke, his underwear was slick with moisture and spotted with blood. His body was glossy with sweat. Every article of clothing was sticking to him and uncomfortable and his blankets were too heavy and his room was too stuffy- He wanted to get out. He kicked the blankets off of him, and was met with tongues of cold air licking at him. He trembled, a soft keen coming from his parted red lips. His stomach hurt, just as it did at the beginning of any Omega’s heat. He desperately tried to pull off his clothing, but his arms were weak and felt like gelatin. His cock was already straining against his undergarment, his holy twitching and wet. He wanted to touch himself, but his body wouldn’t move. What was happening to him?

He was too busy drowning in self-pity to notice the door to his apartment opening, a large body strolling in and hoisting him up bridal-style. His arms dangled uselessly by his sides. All he could do was nestle his head into the welcoming Alpha heat that held him.

There were voices speaking around him, but Armin couldn’t pay attention to anything but the feeling of need twisting in his stomach. He squeezed his eyes shut, the tears that gathered in his orbs making anything too blurry to see anyways.

Someone was calling his name.

“Armin.” He was jostled around in the arms of the Alpha that held him. “Armin, listen to me. Armin.”

Who was speaking? Who was it?

“Do you remember the test you were told about? With sexual intercourse?”

Of course Armin remembered. He could barely nod.

“Do you want to do it? Do you want to have sex with an Alpha and a Beta?”

Yes, he did. Armin wanted it so badly. His body clenched, needing something, anything big to fill him up. A lewd moan came from Armin. It hardly sounded like it belonged to him.

“That’s answer enough…” Another voice spoke.

“Bring him to the observation room. Send the first one in immediately.”

“And blindfold him. I don’t think he would want to know who was… yeah.”

Why were they talking about him like he wasn’t there? Well, Armin didn’t feel like he was there. He felt like he was drowning in a pool of heat.

He was placed upon a cool surface, and the Alpha scent fled from him after a soft fabric was tied around his head. Armin grasped through the air, trying to find the alluring Alpha scent once more. It was nowhere to be found. A wail escaped Armin, and his shaky arms fell beside him, eventually finding their way down to Armin’s crotch. Armin touched himself, and it felt like he was touching himself uselessly for hours (when it was really only minutes) until a warmth pressed against him.

A slobbery, kissing warmth. A heavy warmth that was pressing and rutting against Armin and all Armin could do was rut back. The heavy, numbing feeling had fled from his body and he now felt as light as air. He clutched the body that was atop him. He recalled himself returning the sloppy, open mouthed kisses until the mouth was yanked away and brought attention to his neck. Sharp canines bit into his soft skin, leaving bruises that would only darken later. The mouth lowered, latching onto a swollen nipple and pinching the other with a free hand.

Armin’s senses were going into overdrive. All he could feel was pleasure, and it was overwhelming. He couldn’t comprehend anything except the scent of Alpha stench that wafted throughout the room.

There were hands on his chest, and in the next instant they were pulling apart his naked thighs. When was Armin undressed? Sharp teeth dug into any visible expanse of skin, marking him like a valuable prize. Thick, rough fingers invaded his twitching hole. A welcome intrusion. It started off with one, which turned to two, and eventually four fingers thrusting in and out of Armin.

Fingers weren’t good enough for him.

“More, more.” He sobbed, his voice already hoarse from his moaning and crying.

The Alpha happily obliged, sinking a thick length into Armin the same time teeth dug into the congenial gland on his neck. Armin screamed as he came for the first time.

He was brutally, thoroughly fucked. His legs were held back, his knees on the bed on either side of his head. Armin didn’t remember being that flexible.

By the time a heavy, sticky warmth filled Armin’s insides, he had climaxed twice. The knot filling him deep inside made him orgasm for the third time.

All too soon, the Alpha had left him. Armin was far from finished with his heat. Before he could start wailing and touching himself again, another scent filled the room. Beta.

Armin crooned happily, flipping himself over and readying on all fours. The Beta approached and clambered onto the bed, staring at Armin’s quivering thighs and convulsing hole. A tongue pressed against his pink anus and wiggled inside. Armin squealed with delight, pushing his fat ass back against the convivial Beta. Two fingers wiggled in beside the tongue on either side, pulling his walls apart for the Beta. Armin was tongue-fucked for a good minute until the Beta had enough. The tongue was yanked out and replaced with a throbbing dick, much to Armin’s joy.

“Move.” A growling voice snapped, and Armin obeyed to the dominating pheromones of the Beta. He fucked himself on the thick length. It wasn’t as big as the Alpha he just had, but it was enough for horny Armin.

The beta draped his body over Armin, suckling on his shoulder blades and leaving hickeys down his spine. Hands were dusting over his body, feather-light touches teasing him till tears poured from underneath the blindfold.

“C-Can’t… I can’t…” Armin sobbed, his movements becoming jerky and laboured. “Please, please, please…! F-Fuck me, please!” He begged. Where did this foul language come from?

The beta chuckled, smooth and sexy, in Armin’s ear. “Cute…”

The man raised Armin’s shaky hands, bearing them against the metal headboard. Armin arched his back, this new position making him feel more available than ever. Then, he was fucked. The experienced Beta knew exactly how to twist and turn to make Armin scream. Long jabs went into his prostate, and only three were needed to make Armin convulse and orgasm.

“Don’t stop!” Armin moaned, his voice laced with lust.

Of course, the Beta didn’t stop. He fucked Armin till he was satisfied, and even after then, using his knot to pull Armin to nirvana. His hands were gripping Armin’s hips painfully tight, surely to cause bruises later.

Armin was unconscious by the time the Beta left the room. It didn’t last for long, and as soon as Armin was awake he was scrambling out of the bed and blindly grasping for the door, his cock dripping and a near painful need brewing deep inside. He needed to find the alluring scent of Alpha and Beta that still lingered in his room.

The sound of a door opening made Armin stop in his tracks. Another Beta had entered the room. Armin stumbled over, grasping and kissing at anything he could. It was a neck, it seemed, which he eagerly sucked on.

“Excited, aren’t you?” The Beta laughed and started to push Armin back onto the bed.

“Yes, yes… please…!” Armin whined, pushing out his Omega scent to the Beta, hoping the other would get the drift.

“You sound drunk. Are you drunk on all the dick you’re getting?” The Beta had sat on the bed, and pulled Armin on top. Armin instantly grinded on him.

“Ooh, yes…! More, more…” He was babbling. He didn’t know what he was saying, he was just going along with what the Beta was saying. Anything to release the heat that was burning his core.

“More? Do it yourself.”

Armin nearly cried at that harsh command. Nonetheless, his hands went down to pump his aching hard-on and push fingers into his body. Nothing would stifle the desire inside.

“N-No... Nooo…” He sobbed. His fingers couldn’t reach inside of him properly, and his small hand was too jerky to bring pleasure to his cock.

The Beta laughed, and Armin wanted to growl at him. How dare the Beta growl while Armin was nearly dying? That was an overstatement.

“Oh, Armin.” His hands were pulled away, placed by more skilled hands. Armin leaned into the Beta, panting heavily. Only two fingers were in his arse, and the hand pumping his cock was languid. Armin jerked his hips, and the movements from the Beta stopped.

“No, no, please!” Armin sobbed, entwining his hands into short hair and pulling.

“Beg for it, Omega.” The Beta breathed into Armin’s ear, nibbling on the lobe.

“I w-want your cock, please, inside of m-me, in my ass! I-I’m so wet for it, I w-want it so bad, please fuck me so hard… s-so hard I can’t count to ten. P-Please!”

The Beta hummed. “Till you can’t count to ten, huh? I’ll do it so you can’t count to five.” Armin mewled with excitement.

He heard the sound of something unzipping, and idly recalled that the other two men were not wearing clothes when they touched Armin. He didn’t care about the details currently.

“Look at what you’ve done, Armin.” The Beta purred, bringing Armin’s hands to his own length. “Just your scent has gotten me hard. I’m going to fuck you now.”

“Yess, yeesss!” Armin wept, arching his back at an unbelievable angle.

The Beta raised Armin’s hips and slammed him down onto the awaiting cock. Armin screeched. The Beta didn’t stop for a single moment, instantly raising Armin again and then bringing him down. Deep, he was so deep! Armin’s hands fisted into his shirt, clawing at his back and surely leaving scratches.

“Don’t cum, Armin.” The Beta grunted into his ear, thrusting his hips up to meet Armin’s own bouncing thrusts. “Not till I cum. Can you do that?”

Armin shook his head wildly. “N-Nooo… hngg… G-Gotta cum, cum, please…”

The Beta chuckled, stopping the thrusts to grind deep into Armin, right against his prostate. “Cum, then.”

And, boy, did Armin cum.

“Armin, count to five.” The Beta commanded.

There was no way Armin could go against a voice that authoritative, teeming with Beta pheromones that matched an Alpha’s.

“O-On… One…”

The Beta was ruthlessly fucking into his prostate.

“T-T… Twuuu…. Two!”

Suckling on his ear, his neck, and his nipples. “Such puffy nipples.” The Beta commented.

“T-Th… T…”

One last thrust and the Beta was spewing his seed inside of Armin, his knot growing large and blocking him from pulling out.

“Three!” Armin shrieked, wrapping both arms and legs around the Beta in a choking hold as he rode out his own orgasm. He nearly instantly passed out. His body was limp as the Beta kindly tucked him into the bed, kissing his forehead lovingly before he left the room.

When Armin awoke the second time, his heat had faded considerably. It wasn’t done yet, though. Far from done, and his genitals were still aching for contact. He had come to his senses enough to notice how gross he felt. Sticky with sweat and bodily fluids leaking from his anus. His hair was sticking to his forehead, the blindfold moist from tears.

He sat up slowly, his hips aching at every movement he made. He moaned softly as he pulled the covers from him, his body over sensitized to every touch.

“Good morning, Armin.” The voice sounded so familiar, but Armin couldn’t place it. “Let’s get right to it, then.”

Armin held out his arms expectantly, not wanting to take off the blindfold and see who was doing it- him- this time.  

Footsteps approached him and pulled him too his feet, lifting him up and forcefully wrapping Armin’s legs around the new person. An Alpha. He was trembling with excitement just by the prospect of having an Alpha inside of him again.

He was gently pressed against the wall, and lips attacked his own. It was a gentle kiss, much gentler than Armin had expected. Their tongues danced together. Armin’s hands were wrapped around a thick neck, clutching to a sturdy back. Only one word crossed his mind about this Alpha.

Obviously big, from the length that pressed to his thigh. The Alpha was already naked, unsurprisingly.

“Do you want foreplay, or for me to just fuck you?” The Alpha asked considerately.

“P-Please, just fuck me… I can’t take it…” Armin pleaded softly, his voice scratchy from all the previous moaning he had done.

“I’d be happy to.” The Alpha crooned, licking Armin’s scent gland and pushing four thick fingers inside of him. There was a slight stretch, seeing how large this Alpha was, which only excited Armin more the main event.

After a brief moment of preparing his wet hole, the Alpha pushed his large length inside. Armin squeaked, twitching and trembling until he was fully sheathed upon the large cock.

“S-So… big, oh my god…” He breathed out, his chest heaving with each harsh breath he took. “So big, so good…”

The Alpha took that as a sign that he could move. He thrust into Armin, but it was different than the others. It was gentle, bringing out a purring pleasure instead of a harsh screaming pleasure from him. It was nice, definitely not undesirable.

For the fourth and last time, Armin was fucked gently against the wall. The Alpha traced shapes along Armin’s body with his tongue, suckling on certain areas to leave dark bruises. He was attentive to Armin’s oversensitive nipples and cock. When Armin came, it wasn’t the same feeling of having it ripped from his body. This time, it was gently coaxed from him. His whole body tensed and trembled as he came. Not that much longer after Armin, the Alpha grunted and spilt his seed into the quivering blond boy. The knot was so thick, so tight, and pressing against his prostate so damn good. Armin shivered as a dry orgasm clawed its way to the surface.

“Good boy, Armin… such a good boy.” The Alpha murmured as he brought Armin from the wall they were fucking against and back onto the bed. The knot was still thick and quivering, keeping them attached at their most precious spot.

The large man curled around Armin, dragging the blankets on top of them as Armin dipped into insentience.

**Notes for the Chapter:**

> TRUST ME when I say this isn't how I usually write sex scenes. i was trying to make it kind of... idk... crazy i guess because Armins in his heat and heats are kinda crazy ^^" lmao don't worry next sex scene will be much more understandable im so sorry.  
> two of the armin fuckers might not have anything to do with the story. maybe. maybe all four will have something to do with the story.  
> please comment they make me happy.


	4. Chapter 4

**Notes for the Chapter:**

> this is the shortest chapter yet it just breached 3000 words. but yes here enjoy.

Armin was awoken by a grumbling stomach and an aching backside. He sat up in the bed he was in, every move he made causing distress to build in his joints. He had never been this sore in his entire life. There was a fresh blanket covering his naked body, and a pair of his clothes at the foot of the bed.

It wasn’t that hard to remember what happened the previous night. Or… previous days. Armin didn’t know how long it had been. Heats really mess up ones internal clock. But the fact remained that Armin knew. And it was fucking embarrassing. He was curled so that his back was to the door, and he was crying. His little hands balled into fists and pressing into his eyes, his whole body trembling with the absolute shame that overcame him. How dare they? First Hanji drugged him, and then while he was drugged they convinced him to have sexual intercourse!

While Omega’s were timid and sore and very clingy after their heat, you never wanted to mess with an angry, post-heat Omega. And Armin was a very angry post-heat Omega.

He threw the blankets off of himself and stood from the bed. His pheromones were fuming, but not the lovely sexual scent like before, but an angry type of pheromone. Without even caring to dress himself, Armin stormed out of the room. He knew exactly where he had to go. He felt as if he had broken his tailbone. Every movement ached, until Armin found the most comfortable way of walking was waddling like a fat baby penguin.

It didn’t take long for Armin to figure out that he was on the first floor, the ABO studies floor. He toddled through the lab until he reached the room he was looking for. Without a second thought, Armin pushed into Erwin’s office.

“What the _fuck_ did you do to me?!” Armin growled as soon as he stepped foot into the room.

It would’ve seemed that Armin was interrupting something. Off to the side of the room, where there was a circular table, sat three men. Erwin was standing before them, his mouth open as if he was in the middle of a sentence.

“Armin, please lea-”

“Don’t you fucking dare.” Armin snapped, holding his hands tight to his sides. He was proud when Erwin shut his mouth. Armin’s pheromones were strong enough to make even an Alpha like Erwin listen to him. “What you did to me was sexual assault!”

“You consented to it.” Erwin said softly, his instincts screaming at him to lower his head and bare his sensitive scent gland.

“I was in my heat, which was forced from me by Hanji!” Armin could feel tears pooling in his eyes. The three men Erwin had been talking with didn’t say a word- luckily.

“It wasn’t a forced heat. Much like how birth control can alter a woman’s menstruation cycle, the hormones that Hanji gave you altered your heat cycle.” Erwin lowered his head.

Armin didn’t know what to say. He couldn’t say anything, because he knew that he would cry if he tried to.

Ah, but Armin was crying anyways. It was embarrassing. He cried too much.

Armin didn’t even realize Erwin had approached him till a pair of strong arms wrapped around his naked body. And Armin practically melted. He leaned heavily against Erwin, his legs hardly carrying his own weight at all. His body shook, dazed with the heavy sobs that coursed through him.

The most pleasant crooning sound was coming from Erwin, hushing Armin’s cries quicker than it would usually take. All the while, one of his large hands stroked Armin’s blond locks whilst the other held fast in the small of his back.

“Are you finished?” He susurrated as the crying subsided.

Armin hiccupped.

Erwin pulled off his blazer and draped it over Armin’s shoulders, charmed as the boy was seemingly swallowed by the fabric. “Are you still tired?” He asked, hoisting Armin into his arms like a bride.

Armin shook his head, burrowing into Erwin’s broad chest.

“Are you hungry?”

Armin nodded.

Erwin started off, and as they left the room Armin detected that the three men from before had fled. When did that happen? Armin was carried off by Erwin, to a room that could only be an employee’s lounge. No fair, they didn’t have an employee’s lounge on the biologist floor. Erwin placed Armin in a comfy lounge chair facing a large window.

“What do you want?” The man asked.

“Rice Krispies…” Armin mumbled, twirling a piece of hair around his finger.

Erwin stared at Armin with what could only be admiration in his eyes. “Do you want me to make it for you?” Armin nodded.

So, Erwin searched through the cabinets till he- luckily- found Rice Krispies. There was also Raisin Brand, which remained unopened, and Fruit Loops. He grabbed a bowl, spoon, and milk and then easily prepared the breakfast food. He brought it to Armin, who said nothing as he cradled the bowl between his legs and mushed the cereal under the milk.

“I’m going to get Hanji, so we can all talk about this.” Erwin said softly, placing a comforting hand on Armin’s knee before he stood and fled, leaving Armin with his thoughts.

Armin didn’t _want_ to talk. He wanted to sit and mope. He just felt so shitty, even more so after Erwin left. He ate his cereal in silence, till said silence was rudely interrupted by a door slamming open. Armin jumped and nearly dropped his cereal. Nearly.

“Armin, oh my god, are you okay?” Eren assaulted Armin with questions as soon as he was crouched before his best friend.

“Yes, I’m fine.” Armin reassured, leaning back in the chair. “How did you…?”

Eren looked down at his hands, then back up again, his mouth opening and closing like a fish out of water.

It took Armin less than 10 seconds to understand. “You were… one of the Alpha’s, weren’t you?”

Eren slowly nodded his head, worrying his bottom lip. “I’m sorry…” He snivelled, pulling the bowl from between Armin’s thighs and replacing it with his head. He nuzzled against Armin’s stomach, his hands locking around the slighter boy’s body.

Armin couldn’t be mad at his best friend, especially when he was holding him and nuzzling him and crooning in the nicest way.

But he still could be horribly embarrassed. So much so he began to cry.

At the first sniffle he heard, Eren’s head snapped up. “N-No, Arm, don’t cry!” He wailed softly, hands grabbling at Armin’s shoulders to pull him into an embrace. “I’m sorry. I’m really sorry.”

“Don’t be sorry…” Armin said between hiccups. “I-I’m just… you… you had to see me like that…”

“Armin, I saw you through your scene phase. I think I can handle seeing you as you were last night, especially since I was helping you.” Eren was trying to comfort, but he didn’t know how well he was doing it.

Armin laughed softly, but he still looked sad. And it was breaking Eren’s heart.

“Let’s just forget about it, okay? What happened, happened. We can talk about something different.” Eren thought it was strange for Armin to react this way. Of course Armin would be embarrassed, the boy had always been self-conscious of his appearance, but he also would’ve tried to look at it from every different angle before he started on the self-pity trip. But, whatever. Whatever his best friend was feeling, Eren would be with him.

Armin nodded at the proposition, holding his arms out for Eren. Eren instantly complied, knowing what that meant, and hugged Armin close.

“Bertholt wants to see you…” Eren said once the silence became too crushing. “He’s been worrying about you. Want to go see him?”

“I can’t.” Armin said softly, pressing his cheek into the top of Eren’s head. “Well, I can. But Erwin will be back any second now with Hanji.”

“Ah…”

So the duo waited. Eren didn’t want to leave Armin by his own any longer, so Eren patiently waited with Armin.

Soon enough, Erwin returned with Hanji in tow.

“Armin, I’d like to formally apologize.” Hanji spoke as she stood in front of the blond biologist. “I did not tell you what the side effects of the injection would be, and for that you suffered.” She bowed her head. “I would be grateful if you were to ever forgive me.”

Armin didn’t like this. He loved happy, curious Hanji, not serious and apologetic Hanji!

“It’s fine, I guess…  Of course, next time I expect to know what’s going to happen to me, but… this was a kind of learning experience.” That anal sex felt really good? Yes. “I’m still royally pissed off though.” Armin leaned back in the chair and crossed his arms.

“Yay, Arm isn’t all that upset anymore!” Eren sang happily, nuzzling against his lifelong friend. “You’re thinking logically again.”

Armin scoffed and pinched Eren’s cheek.

“Now that we’ve gotten the formalities out of the way…” Hanji crouched before Armin, beside Eren. “Tell me all about it!”

Armin’s face exploded in colour. “W-Wha…?”

“Armin will not!” Eren exclaimed, glaring at the female beside him.

Hanji just laughed. “No, no. I don’t expect a play-by-play of what happened. Armin, you’re a scientist. How did your body react to this otherwise illegal activity?”

Armin _was_ a scientist. So he needed to start acting like one. “Well…” Armin started. “There wasn’t any necessarily bad reactions, save for an aching body…” He coughed, cheeks tinted a lovely pink. “My hormones feel fine, to me at least. But we’ll never know till we test it.” Armin made a displeased face. “Do we have to do tests?”

“Goodness, no!” Hanji said. “We will do them whenever you’re feeling up to it. Alright, Armin?”

Armin nodded and offered Hanji a kind smile. These people were too nice to him.

“Then, Armin,” Erwin spoke for the first time since he returned with Hanji. “Do you wish to go back?”

Armin nodded. “Ah, but um… first…” His blush spread to his ears and chest. “Can I have some clothes?”

* * *

 

Almost as soon as Armin returned to his own room, the biggest, lankiest Omega ever came running in. Bertholt lay beside Armin on the bed, snuggling into him and absolutely overwhelming the smaller male with his body mass.

“What’s wrong, Bert?” Armin questioned, returning the comforting cuddles.

“Nothing… I don’t know. I just feel like being with you. Especially after all that’s happened to you, with your heat and all…” Bertholt pressed his nose against Armin’s neck, right next to his scent gland, and breathed in heavily. Omega’s were naturally comforting to one another.

“Before they asked me to do the experiment, they asked you, right, Bertholt?” Armin peered down at the dark haired man.

Bertholt froze, his face paling and then turning red. “I- yes…”

The two laid in silence, neither uttering a word and simply sharing the moment of calm between them. Their chests pressed flush together, their steady heartbeats thrumming together in harmony. The quiet _tick tock_ of Armin’s clock that had been passed down for generations rang in the background. It was peaceful, and Armin didn’t want to ruin the beautiful moment they were sharing. But, of course, Armin was a very inquisitive person.

“How did you even end up here?” Armin asked softly, drawing figure eight’s on Bertholt’s shoulder with his finger.

“I came here with Reiner. We lived in a small village in the mountains. It was a village for warriors… You know, it was one of those villages, where they lived with pack mentality instead of humanity?” When Armin nodded, Bertholt continued. Almost every ABO belonged to a pack, but there were few colonies that lived as if they were wolves. “The majority of the population was Alpha. The minority was Beta. Then there was me. I hadn’t displayed Beta in my preteens, nor did I display as Alpha in my teens. Everyone thought that I was a late blooming Alpha, they weren’t uncommon… But when I presented as Omega things went south…”

Armin had cradled Bertholt’s head against his chest, feeling the breath coming from his parted lips tickle his collar bones.

“Everyone thought I was weak and stuff. They thought an omega would be a hindrance to the pack… They were going to kill me, or exile me… But Reiner just up and decided one day that we would leave.” Armin caught Bertholt smiling. “We left and traveled into the city. We didn’t have any proper education, so we couldn’t find jobs… but then we found this lab. It was a blessing, really.”

Armin had started to hum softly, the soft rumble in his chest calming to Bertholt. “That’s the most I’ve ever heard you talk…” Armin commented softly. “But that is a very sad past… I’m really sorry. Are you at least happy here?”

Bertholt suddenly sad up, staring down at Armin with intensity in his eyes. “I am very happy here.”

Armin was shocked for the briefest of moments. His expression relaxed and he pulled Bertholt down upon him into a warm encirclement.

“So am I.”

* * *

 

Things were normal for the next couple of days. Thinking on a whim, Armin had decided to stay home from work for a few days. None of the other in the ABO studies had brought up Armin’s heat, and he was truly thankful for that. The only difference Armin noticed was Bertholt staying closer to him and Eren being more protective than usual. Armin was able to find easy explanations for both occurrences. Bertholt found that he could trust Armin more, or he felt much closer, after sharing such a deep backstory. Eren just felt all the more intimate with Armin after their courting. It was artless.

Armin had already visited Hanji for tests, and he was awaiting the response.

“Does he wear glasses?”

“No.”

Connie flipped down several tiles on his ‘Guess Who?’ game. Armin and Connie were dueling for something very important- the television remote rights for the day. Armin was sitting on the floor across from Connie and Sasha, the game sitting on the coffee table between them. Bertholt was sedentary on the couch behind Armin, reading a book about who knows what, whilst Mikasa sat at the head of the table. She was observing the game with a keen eye. She said that she hadn’t been interested to play, but with the way she was staring at the game it was obvious that she was indeed fascinated. Reiner and Eren were playing each other against the recently bought foosball table, calling out obscenities every one in a while. Annie was most likely in her room, doing whatever social recluses do.

“Is she wearing a hat?” Armin asked, looking through the few people that remained on his board.

“Yeah.” Connie glared at Armin as the blond smugly flipped down three tiles.

“Does your dude have a beard?” Connie asked.

“Yeah, and it looks stupid!” Armin snickered. Connie flipped down a few tiles.

“Is your person A-” Before Armin could ask and totally win the game, Jean entered the peaceful room.

“Armin?” He called, causing Armin to raise his head. “Hanji would like to see you.”

Armin glanced back towards the Beta duo. Both of them were grinning like idiots. “You get the stupid remote.” Armin growled, though he was smiling. “Tomorrow it’s mine, though!” He called as he jumped up, skipping over to meet Jean at the door. Jean held open the door, letting his blond friend out first. The two went off.

“I feel like I haven’t been seeing you at all since you volunteered at the studies…” Jean groused, shuffling his feet against the tile floor.

“You’re the one who was desperate for me to join.” Armin pointed out.

“Yeah, but…!”

Armin laughed, a sweet sound that chimed through the quiet hallway. “Are you jealous? Do you want to spend more time with me?”

Jean pouted and nodded at the ground.

“Then we will.” Armin said. By the time their conversation had finished, they had already reached Hanji’s laboratory. They entered the clean space, immediately being met with a chime of ‘Hello!’ from Hanji.

“Just go sit down, Armin.” She said.

Armin waltzed over to the bed that was covered in a crisp sheet of sanitary paper. He hopped on top, kicking his legs back and forth as he waited for Hanji. She was saying something to Jean that Armin could not catch. When the two separated, Hanji made her way over to Armin on her wheeling chair.

“How have you been lately, Armin?” Hanji asked, wiggling Armin’s knees around.

“Not that bad. Nothing really has changed, except I don’t feel like going into work at all.” Armin said with a shrug.

Hanji responded, “That isn’t that abnormal.”

Armin tried to understand what that meant, but he couldn’t put his finger on it.

“Let’s wait for Jean to return, yeah?”

Armin nodded, feeling an odd sense of suspicion rise from the pits of his stomach. Hanji and Armin spoke between one another as they waited, just about random things that had been happening in their life. Hanji’s niece had entered kindergarten.

Finally, after what seemed like a decade of waiting, there was a knock at the door. Hanji called for them to enter, and in came Jean with Eren, Levi, and Erwin in tow. Jean and Eren were glaring at each other, probably being silenced mid argument, whereas Levi and Erwin looked as professional as ever.  

Hanji started. “Uh, there’s not really much space to sit, but you all might want to stay standing for this. Armin, you can stay sitting, don’t worry.”

Hanji fiddled about uncomfortably, trying to find the right words to say what she was about to say. It only made Armin feel all the more suspicious.

“Well, there’s only one way to say this.” She finally sighed. “Armin is pregnant.”


End file.
